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    <title>Document</title>
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    <script>
      function Star(uname, age) {
        this.uname = uname
        this.age = age
      }
      Star.prototype.sing = function () {
        console.log("我会唱歌")
      }
      var shiyuan = new Star("石原里美", 18)
      // 1. 只要是对象就有__proto__ 原型, 指向原型对象
      console.log(Star.prototype)
      console.log(Star.prototype.__proto__ === Object.prototype)
      // 2.我们Star原型对象里面的__proto__原型指向的是 Object.prototype
      console.log(Object.prototype.__proto__)
      // 3. 我们Object.prototype原型对象里面的__proto__原型  指向为 null
    </script>
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